Fused Filament Fabrication (FFF) is the technology of extruding plastic through a nozzle to form physical models. The physical models formed by FFF may be used for functional prototype testing, for reviewing fit and function of physical parts, or in low volume production scenarios. FFF allows for physical parts to be created quickly and without the construction of costly tooling (in the case of Injection molding for example). FFF is also referred to as Additive Manufacturing or 3d Printing, and most generally as rapid prototyping. Further discussion of conventional FFF designs and methods of operation are found in U.S. Pat. No. 7,604,470 that issued on Oct. 29, 2009 assigned to Stratasys, Inc. The contents of U.S. Pat. No. 7,604,470 are incorporated herein by reference in its entirety.
Among many of the benefits of FFF is the ability to extrude a number of different plastic materials with different extrusion nozzles. The ability to extrude different plastics allows for the selection and use of plastic based on the physical or mechanical properties which are selected based on the products finished application. Additionally, the use of different sized nozzles allows for physical models to be created with very fine detail, using a very small nozzle; or conversely for less detail and higher production speed using a larger nozzle.
The limitations with the multiple extrusion heads for FFF machines is that for each nozzle there is a stepper motor which drives the plastic filament through the heated nozzle. As more traditional extrusion nozzle/motor combinations are added, the footprint of the extrusion head grows which reduces the size of the physical model that can be created. This occurs because each nozzle must be able to reach the extents of the print area in the x-axis and y-axis directions.